Application of fuzzy classifier fusion in determining productive zones in oil wells

International audienceThis study is an application of data fusion techniques, especially fuzzy theory, in determining oil producing zones through four nearby wells, located on an oil field in south west of Iran. Two fusing techniques, used here are based on Bayesian and fuzzy theories. At first, two Bayesian classifiers are being constructed by training in two different wells; then a fuzzy operator, called Sugeno discrete integral, is used to fuse outputs of two mentioned Bayesian classifiers. Finally, it is concluded that using fuzzy classifier fusion improves not only certainty and confidence of decision making, but also generalization ability of determining productive zones

WHOLE SPACECRAFT VIBRATION ISOLATION: A COMPARISON OF PASSIVE VS. SEMI-ACTIVE ISOLATION DESIGNS

The launch phase is the harshest mechanical environment a spacecraft experiences through its lifetime. The severity of the vibrations during the launch phase poses a serious challenge for the design of the spacecraft which generally contains many sensitive electronic components. The need to guarantee the launch survival of the spacecraft has instigated a significant amount of research in the field of vibration isolation of the whole spacecraft, which resulted in development of various passive vibration isolation systems and their widespread use since two decades ago. The present study is aimed to analyze the feasibility of implementation of semi-active vibration isolation system instead of a passive one and to compare its potential benefits in attenuating the vibrations transmitted to the sensitive components of the spacecraft during the launch phase. First, the passive system has been studied and a methodology for design optimization of the multi-degree of freedom system in frequency and time domain has been formulated. The optimized passive system is then used as a baseline to compare the performance of the optimal passive isolator with that of a semi-active system. Semi-active control strategies based on Skyhook (SH) and combined Skyhook and Acceleration Driven Damping (SH-ADD) have been utilized to control the damping of the isolator between spacecraft and launch vehicle to attenuate vibration. The results showed that while semi-active system has a significant advantage over passive system to attenuate vibrations when the excitations are harmonic or narrow band, the results are not as promising when broadband random excitation, which is a realistic model of the excitations that the spacecraft experiences during launch, is considered. This calls into question the practical effectiveness of the semi-active system to be used in whole spacecraft vibration isolation system. Further research work with experimental tests are required to verify if semi-active systems can have a practical application in whole spacecraft isolation system

Identifying productive zones of the Sarvak formation by integrating outputs of different classification methods

International audienceSarvak formation is the second major carbonate reservoir in Iran. There are several geological, petrophysical and geophysical investigations which have been carried out on this important reservoir. In this work, Sarvak is studied to find productive zones. At first, four different methods were used to identify producing intervals from well log data and well test results. Then, final zoning is generated by integrating outputs of these four methods. One of them is the conventional cutoff based method; the other three methods are based on flow equation, Bayesian and fuzzy theories. Thereafter, by considering the classification correctness rate of each classifier in each well and technique of majority voting, a unique zoning for Sarvak formation is presented. Based on the final zoning, the whole Sarvak interval is divided into seven zones. Three of them are classified as oil producing zones, two of them cannot be classified as conventionally producing zones, and the remaining two are water producing. Zone number 2 not only has the highest production rate, but also is the most homogeneous zone among the productive zones. The novelty of this research is using well test results in defining productive classes, which improves the certainty of classification in comparison with previous works that were based on core analysis and log data

ISTRAŽIVANJE UTJECAJA MIKROPARAMETARA NA SVOJSTVA ČVRSTOĆE STIJENE

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.Svaka je stijena stvorena od čestica čijim se međudjelovanjem određuju njezina mehanička svojstva. Budući da je vrlo važno provesti opsežne studije o povezanosti mikroparametara i makroparametara stijene, u ovome su radu istraživani učinci nekih mikroparametara na svojstva čvrstoće i ponašanje pukotina stijene numeričkim simulacijama jednoosne tlačne čvrstoće (UCS) i brazilske vlačne čvrstoće (BTS). Ispitivani mikroparametri uključivali su kontakt čestica, omjer kontaktne krutosti, koheziju veze, vlačnu čvrstoću, koeficijent trenja i kut trenja, a mehanička svojstva stijene bogate kromitom bile su osnovne vrijednosti ispitivanih mikroparametara. Utvrđeno je kako su najvažniji mikroparametri na ponašanje stijene kod tlačenja kohezija veze, vlačna čvrstoća veze i koeficijent trenja. Također, vlačna čvrstoća ima najveći učinak u vlačnim uvjetima. Ovaj mikroparametar povećava vlačnu čvrstoću (do 5 puta), minimalizira destruktivne pukotine i povećava odgovarajuće naprezanje (gotovo 2,5 puta) pri kritičnome naprezanju

Application of Bayesian in determining productive zones by well log data in oil wells

International audienceExploration specialists conventionally utilize a cut-off-based method tofind productive zones inside the oil wells. Using conventional method, payzones are separated crisply from non-pay zones by applying cut-off values onsome petrophysical features.In this paper, a Bayesian technique is developed to find productivezones (net pays), and Bayesian Network is used to select the most appropriateinput features for this newly developed method. So, two Bayesian methodswere developed: the first one with conventional pay determination inputs(shale percent, porosity and water saturation), the other with two inputs,selected by Bayesian Network (porosity and water saturation). Twodeveloped Bayesian methods are applied on well log dataset of two wells:one well is dedicated for training and testing Bayesian methods, the other forchecking generalization ability of the proposed methods. Outputs of twopresented methods were compared with the results of conventional cut-offbasedmethod and production test results (i.e. a direct procedure to checkvalidation of proposed methods).Results show that the most prominent advantage of developedBayesian method is determination of net pays fuzzily with no need to identifycut-offs, in addition to higher precision of classification: nearly 30%improvement in precision of determining net pays of first well (training well),and about 50% improvement in precision of determining productive zonesthrough the generalizing well

The Effects of Different Roughness Configurations on Aerodynamic Performance of Wind Turbine Airfoil and Blade

In this research, viscous and turbulent flow is simulated numerically on an E387 airfoil as well as on a turbine blade. The main objective of this paper is to investigate various configurations of roughness to find a solution in order to mitigate roughness destructive impacts. Hence, the sand grain roughness is distributed uniformly along pressure side, suction side and both sides during the manufacturing process. Navier-Stokes equations are discretized by the finite volume method and are solved by SIMPLE algorithm. Results indicated that in contrast with previous studies, the roughness will be useful if it is applied on only pressure side of the airfoil. In this condition, the lift coefficient is increased to and 1.2% compare to the airfoil with rough and smooth sides, respectively. However, in 3-D simulation, the lift coefficient of the blade with pressure surface roughness is less than smooth blade, but still its destructive impacts are much less than of both surfaces roughness and suction surfaces roughness. Therefore, it can be deduced that in order to reveal the influence of roughness, the simulation must be accomplished in three dimensions.Article History: Received Jun 12th 2017; Received in revised form August 27th 2017; Accepted Oct 3rd 2017; Available onlineHow to Cite This Article: Jafari, K., Djavareshkian, M.H., Feshalami, B.H. (2017) The Effects of Different Roughness Configurations on Aerodynamic Performance of Wind Turbine Airfoil and Blade. International Journal of Renewable Energy Develeopment, 6(3), 273-281.https://doi.org/10.14710/ijred.6.3.273-28

Organizational conformity as an entrepreneurial response to the changes in internationalization process: A study of IT-oriented firms in Saveh

The purpose of this study is to explore the impact of organizational entrepreneurship on organizational adaptation in response to change in the internationalization process. The statistical population of this research is Information Technology Organization of Saveh in 2017, among which 230 people were selected. In this study, the simple random sampling method is used to select individuals. The findings show that cultural policies indicate that international businesses still face difficulties in providing expertise to operate in international markets. The most important factor that an international entrepreneur has pointed to in developing their activities in this dimension is the development of international business networks such as industrial clusters. International entrepreneurs have introduced the impact on customs rules for the creation and running of international businesses as the most important factor of this section. International entrepreneurs in this dimension have given the highest score of the development of export-oriented infrastructures, such as communication technology

Effects of Preemptive and Preventive intravenous Paracetamol on postoperative pain and opioid consumption in patients undergoing laparoscopic nephrectomy

Background: Adequate pain control is a goal in post operative recovery. However opioids provide good analgesic effects, their side effects such as postoperative nausea and vomiting (PONV) limit their administration. Intravenous Paracetamol as a safe and well tolerated drug with lower side effects can be used instead of opioids for pain management.Objectives: The aim of this study is to compare preemptive or preventive administration of paracetamol with placebo group to investigate its effects on pain control and opioid consumption in patients undergoing laparoscopic nephrectomy.Patients and Methods: Ninety patients were randomly divided to three groups. Preemptive group received 1 gr paracetamol in 100 ml normal saline 30 minutes before induction of anesthesia, Preventive group received 1 gr paracetamol in 100 ml normal saline before closure of the skin and placebo group just received 100 ml normal saline. Post surgical pain was assessed using Verbal Rating Scale (VRS). Pethidine 0.25 mg/kg was administered and repeated each 10 minutes to control pain. Pain scores, total dose of opioid and symptoms like nausea and vomiting were recorded. Results: Preemptive and Preventive groups had lower pain scores than placebo group. Opioid consumption and PONV were significantly higher in placebo group. No significant differences were observed between Preemptive and Preventive groups.Conclusion: IV Paracetamol can provide an adequate pain control with low side effects and may be an effective choice in management of post operative pain in patients undergoing laparoscopic nephrectom